A. Field of the Invention
The present invention relates to media for transferring images and, in particular, to an image transfer sheet and a corresponding method for using the sheet in conjunction with ink jet printers.
B. Prior Art
Human beings have long been fascinated with transferring images from one media to another. In the 1960's, children and adults alike used Silly Putty.RTM. to transfer images onto a wide range of other surfaces. One common example of this technique was to use Silly Putty.RTM. to transfer colored comics from the Sunday newspaper to another surface. A person would roll the Silly Putty.RTM. on the comic to transfer the image from the paper to the surface of the Silly Putty.RTM.. The Silly Putty.RTM. would then be rolled onto another surface to transfer the comic to a surface such as a countertop. The Silly Putty.RTM. approach worked fine for temporarily transferring comics or other images onto a limited range of hard surfaces, but not onto less rigid surfaces such as fabric T-shirts, for example. To transfer an image onto a T-shirt, an individual had to purchase a pre-printed iron-on transfer sheet. To use this product, the purchaser would place the sheet image-side-down onto a T-shirt and then iron the sheet to transfer the image onto the fabric of the shirt.
Iron-on image transfer sheets had a number of limitations, however. First, since the sheets were pre-printed, individuals purchasing these products were limited to selecting from a narrow range of standard image designs. The individual could not be creative and design their own image.
Second, these products required the end-user to be somewhat skilled when transfering the image onto the desired substrate, such as a T-shirt. If the end-user did not hold the image transfer sheet perfectly still while ironing it, the image on the shirt was blurred. Thus, the end result was that an individual using these products had to be satisfied with an end-product that did not meet their aesthetic criteria, or else throw the image-bearing substrate away and start all over again. Thus, these products did not permit the substrate to be re-used.
Another limitation of these products was that they required ironing to transfer the image to the substrate. As an alternative to ironing, images could be transferred to T-shirts and other substrates with a silk-screen process. Typically, silk-screening requires the user to place a custom order with a custom printer. However, by placing a custom order, the individual lost his/her opportunity to directly create his/her own personalized products. Additionally, the expense and time delay in receiving the final end-product were significant disadvantages to placing a custom order.
The image transfer field took a new turn in the 1990's, when ink jet printers became widely popular. T-shirt transfer sheets were developed onto which a user could print a custom image using software installed on a personal computer, then use an ink-jet printer connected to the computer to print out the custom image in reverse form onto the T-shirt transfer sheet. The image on the T-shirt transfer sheet would then be transferred onto a T-shirt by laying the sheet print-side down on the substrate and then ironing the back side of the sheet. The printed image would then appear on the T-shirt. With the introduction of these products people could, for the first time, compose a custom image on their personal computer, then put that image onto a T-shirt using little more than an ink jet printer and an iron.
As examples of commercially available ink jet products for image transfer, Canon now sells an ink jet compatible iron-on T-shirt transfer sheet under the product code TR-101. Similarly, Hanes sells an ink jet compatible iron-on T-shirt transfer sheet under the trade name Hanes T-ShirtMaker. More information about the Hanes T-ShirtMaker is available on the Internet at http://www/hanes2u.com. Both the Canon and Hanes sheets require heating the sheet with an iron or other hot device before the image will transfer. As an alternative to printing an image onto the Hanes sheet with an ink jet printer, the user may draw an image directly onto the sheet with special crayons and then iron the crayoned image onto a T-shirt.
While these types of sheets represent a step forward, they have various limitations. Many of the sheets transfer at most only about 60%-80% of the printed ink onto the substrate. Consequently, the colors do not appear as brilliantly on the substrate as they should, and images are not nearly as crisp. Secondly, the image is permanently fixed onto the T-shirt as soon as it has been ironed on. If the user does not like the image, or if the image did not transfer properly, there is no way to remove the image from the substrate. The user must either throw the substrate away and begin anew, or use the product in its flawed state.
A third limitation of these sheets is that the entire image sheet transfers with ironing, even areas that are not printed and that do not contain the image. For example, a circular printed pattern is often ironed on as a large square, leaving an unsightly square edge around the circular printed pattern and unnecessarily stiffening the substrate. As an alternative, the instructions for Canon's product code TR-101 suggest cutting out the printed image from the image transfer sheet as follows:
"For best results, cut away the unprinted portion of the transfer, coming as close to the printed area as possible. If an unprinted portion of the transfer is applied to the fabric it will cause the fabric to become stiff"
One problem with this approach is that it requires considerable cutting skill on the part of the user. If the user snips a little bit too far, he may cut into and thereby damage the printed image. If the image is at all intricate, considerable time may be necessary to cut about the image, and it may be impossible to remove the unprinted central portion of the transfer. Also, if the cut is not perfect, the unprinted area about the edge of the image may have an uneven, unsightly appearance once transferred to the substrate.
Fourth, the transfer sheets are generally designed to transfer images only with simultaneous heat transfer and fixing. This imposes an additional limitation as the user is frequently limited to selecting those fabrics or other surfaces that can accept the simultaneous heat transfer and fixation without being damaged. There are many instances when a user wants to transfer a custom-printed image onto surfaces that cannot be heated. For example, custom designed images and/or phrases cannot be ironed onto an automobile, or onto other surfaces such as glass windows, three-ring binders and tiles, to name a few. Other surfaces that are desirable for image transfer include paper of various types, file folders, report covers, sheet protectors, plastic and vinyl binders, glass, mirrors, cardboard, stainless steel, aluminum, painted metal, wood, ceramics, plastic laminates such as FORMICA, furniture, overhead transparencies, toys, and a wide variety of other surfaces.
Another drawback with some of the prior art T-Shirt image transfer sheets is that even after the image has been transferred, the shirt must be washed in a vinegar bath in order to set the image. The requirement of making the image permanent by immersing the image-bearing substrate into a vinegar bath adds yet another step to a complicated and hazardous process.